This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The primary objective of this proposal is to assess the efficacy of the drug given two times daily compared to placebo. The secondary objectives are: 1) To assess the effects of this drug on mood, cognition, fatigue, impulse control, daytime sleepiness, and night time sleep compared to placebo;2) To compare the tolerability among the treatment groups over 12 weeks. The proposal is a randomized, double-blind, active and placebo controlled, parallel-group study. The proposal plans to enroll a total of 295 patients in 50 centers, with 74 patients in each study group.